EFFECT OF ORAL AND INHALED CETIRIZINE IN MILD ASTHMATIC PATIENTS

Objectives: The effect of an inhaled and oral HI antagonist has been compared in the same patients.Material and Methods: We have compared the effect of a single dose of nebulised (1 ml - 10 mg /ml) and oral (15mg) cetirizine to a matched placebo in a double blind double blind double dummy cross over study in 10 atopic asthmatics with moderate airflow obstruction mean (sem) age 52 (5.22) years, mean predicted FEV1 59 (3.9%).Results: The data was analysed by applying the multiple Regression analyses and chi square statistical methods. There was no significant difference in the baseline FEV1 on three study days. The maximum mean percentage increase in FEV1 after placebo, nebulised and oral cetirizine were 11.7 (2.8); 11.3 (5.5) and 21.8 (3.7) respectively. Significant bronchodilation was observed at 60 (P<0.02) ,120 (P<0.02) and 180 minutes (P<0.05) after oral cetirizine compared to placebo. Four patients developed transient bronchocostriction after inhaled cetirizine. These results suggest the presence of a local histamine tone in the airways.Conclusion: Ordinary doses of currently available HI receptor antagonist have minimal bronchodilator and bronchoprotective activity. In severe persistent asthma, HI receptor antagonist have no significant clinical effect, however in moderate asthma clinical benefits of HI receptor antagonist are apparent. The participation of antihistamine in the allergic inflammation including asthma must be reexamined, since the effect of histamine are more widespread and further studies are needed to evaluate its role in the management of asthma.